Fourth-century church history is simultaneously the history of the emperors, Christian with most of the Constantinian dynasty, briefly pagan in Julian; but Julian's disastrous campaign against Persia in 363 was taken to be a sign that his old polytheism offered no security to the cause of Roman power and imperial domination. His failure and death provided a contributory cause of Christian success in the conflict with paganism. In this age it was almost axiomatic that military victory was a providential gift not granted to people whose religious rites or moral conduct failed to propitiate heaven. Prayers win battles, wrote the pagan Libanius (or. 20. 48). Yet from 375 onwards the barbarian influx in the west transformed the operations of both state and church. The intermingling of church controversy with imperial politics sometimes solved problems for both church and state, but could also create them. The Christian dissensions of the fourth and fifth centuries are misread if they are naïvely interpreted as mere struggles for power. What most mattered to the contending bishops was the theological teaching of their tradition. At Nicaea in 325 Constantine the Great was determined to achieve harmony and consensus, and largely succeeded. The authority of his great council would have been weakened if rival factions had been allowed to create a split with a substantial minority opposed to the central decisions. Wise bishops also wanted consensus and unity in accord with the tradition of scriptural understanding which they had received. There were enemies to combat: pagan critics who read Celsus and Porphyry, schismatics who, while in essentials orthodox, vehemently dissented (like Donatists on moral grounds) to the point of rigid separation from the main Christian body, and heretics who longed for their version of the faith to be accepted as at least a valid option, best of all as the more authentic form of divine truth. In Christian history, however, the most passionate disputes have been, and were in the fourth century, between those who stood very close to one another. The issues were too often logomachies, a feature already troubling as early as 2 Tim. 2: 16, 23.